Bellows assembly for refrigerant control valves



y :inventor w/ence C. JWM @fue Apnl 16, -1940.V 1... SMITH BELLOWS ASSEMBLY FOR REFRIGERANT CONTROL VALVES Filed Dec. 2, 1936 (Ittorneg g 2t and the chamber l2.

Patented Apr. 16, 1940 UNITEu STATES BELLOWS ASSEMBLY FOR REFRIGERANT CONTROL VALVES y Lawrence C. Smith, Kenmore, N. Y., assigner to Fcdders Manufacturing Company, Inc., Buffalo, N. Y.

Application December 2, 1936,x serial No. 113,877

2 Claims.

This invention relates to refrigerant expansion valves, and it has particular reference to im-I provements in valves of this type enhancing their economy and eciency in operation. ti. Among the objects of the invention are to provide a refrigerant expansion valve in which adjustment of the valve setting may be eiected from the high side of the refrigeration system, in which a novel valve actuator may be` employed, and in which actuating springs may be avoided in the low side of the system, and otherwise to improve the nature of such valves, in modes which will be hereinafter more fully explained and set forth in the appended claims. A typical valve embodyingthe present invention is illustrated in the accompanying drawing, wherein:

Fig. 1 is a sectional View of the valve;

Figs. 2 and 3 are plan views of portions of the power element, showing the method of connecting the same;

Fig. 4 is a section, showing in detail and on an enlarged scale the valve and seat construction; Fig. 5 is a section taken on the line 5 5 of Fig 1;

Fig. 6 is a side elevation of the power element prior to assembly with the mounting body; and

Fig. '7 is a sectional View of a control element which may be used with the valve to form an automatic expansion control.

The elements of the valve are organized with a mounting body lll which is formed with coaxial bellows and valve chambers ll and l2 respecr tively, separated by a partition i3. An inlet passage Hl in the body l2, which may be connected to the high pressure side of a refrigeration system through a connection l5, communicates with the valve chamber l2 through a connecting passage l5.

The partition lil is formed with an axial opening Ill which serves to receive a seat member I3. As shown in Fig. 4, this member is formed with three axial holes 2l, 22, 23' of progressively 4K5 larger diameters. The hole 22 defines an internal shoulder 2t which serves as a seat for a valve needle 25 which is slidably mounted in the hole 23.) Radial holes 26 in this portion of the seat member provide communication between the seat The seat member contains radial holes 2l leading into the axial holo 22 and terminating in an external circular groove 28, which in turn communicates with an outlet passage 30 terminating in a tting portion 29A which may receive suitable connections for attachment to an evaporator of a refrigeration system.

The upper axial hole 2l serves as a bearing for an actuator pin 3l, whose upper end extends therefrom into the bellows chamber Il. The lower end of the pin projects through the hole 22, and its terminal portion 32 is received inha socket 33 formedin the tip of the valve needle 25. It will be apparent that a force applied to the'pin 3l will unseat the valve needle, Where- 10 upon `refrigerant will enter the hole 22 about the pin and finally be; directed to the outlet passage 32.

Adjustable means Aare provided for retaining the valve' needle in Seated position, comprising a saddle member 35 having a central hole 36 for receiving a reduced pin portion 3i formed on the needle 25 and an upwardly extending annular portion providing a spring seat 31 for one end of a compression spring 38. Thel remaining end mi of the spring is seated on a-nut 39 which is tapped to receive a threaded adjusting stem t0. Rotating movement of the nut is prevented vby keys lll formed thereon, which engage in opposed keyways2 on the wall of the chamber i2 (Fig. 5). y The stem l0 is formed with a shouldered portion i3 which bears against a cap M which is soldered to the open end of the chamber l2. The cap,` contains a gland structure including a packing t5 and a gland nut t@ through which remaining portions of the stem 39 project. A cap nut il is secured to the exterior of the cap, and it contains a gasket which engages the end of the cap and thus provides an additional seal against leakage of refrigerant from the chamber l2. i

The valve, as thus far described, may be organized with various types of control instrumentalities which may operate directly on the protruding actuating pin 3l. In Fig. 1, for example, it is' combinted with a thermostatic element to provide a thermostatic expansion valve. This unit comprises a bellows 5U which is secured to an annular member t8 at one extremity, and to the radial flange 5I of a head 52 at its remaining M extremity. A casing encloses these elements, and the member 4B is soldered to the lower end thereof, thusl forming a sealed thermostatic chamber 54. A thermostatic bulb 55 communicates with the chamber 512 through a tube 56. A circular mounting ange 49 is formed on the exterior of the casing 53.

It is preferred that the thermostatic unit be of a unitary structure so that it may be handled or shipped separately without danger of rupture of the bellows under adverse temperature conditions. To prevent excessive collapsing of the bellows, a stop structure is provided by forming a pair of opposed ears 51 on the upper end of the head 52 (Fig. 3) which are engageable with an underlying internal ilange 58 formed in the casing 53. The flange 58 is formed with an orice 60 (Fig. 2) which is adapted to permit passage of the upper end of the head 52, including the ears 5T, therethrough. A compression spring 59 may be disposed between the head 52 and the casing 53. l

To assemble the thermostatic unit, the head 52, bellows 50, and annular member 4B are rst soldered together, and then inserted in the casing 53 with the upper end ofthe head inserted through the orifice 60 of the casing. 'I'he head and casing are then relatively rotated to position the ears 51 over the flange 58 of the casing, whereupon the member 48 is soldered to the casing to x the elements in this position. Thus, it will be observed that the head 52 and casing 53 are connected by a joint of the bayonet type.

To assemble the thermostatic unitair/ithv the valve body l0, it is inserted in the bellows chamber Il and the mounting flange 59 is then soldered 4to the extremity of the body. When thus positioned, the lower end of the head 52 is adapted to contact the projecting actuating pin 3| upon collapse of the bellows under pressure, thus permitting the valve to be operated by the thermostatic element.

To protect the thermostatimlcharnber from a too rapid heat exchange action with the expanding refrigerant delivered through the passage 30,

.a small tube 62 is inserted in the passage 30 to convey the refrigerant to the extremity of the tting portion 29. The passage 30 is formed with an enlarged counter-bore 63 for a substantial distance, so that the tube 62 only contacts a small section of the body adjacent to the seat member I8. The bellows chamber Il communicates with the counterbore 63 through a drainage hole 64 which prevents oil, which may escape past the pin 3|, from accumulating therein. Through the provision of the tube 62, the refrigerant is prevented from expanding in its passage from the valve body. In addition, direct thermal contact between the tube and body is retained at a minimum, to the .end that the body is-retained at a somewhat higherv temperature than the evaporator portions of the refrigeration sys-l tem.

.The thermostatic expansion valve above described may be converted into an expansion or pressure responsive valve by simply omitting the thermostatic bulb and tube and providing a heavier `spring 59. In operation of this valve, the force exerted by the adjusting spring 38 plus the force of the refrigerant pressure Within the bellows 50 will oppose the combined forces of the spring 59 and atmospheric pressure on the opposite side of the bellows. Thus, upon proper adjustment of the spring 38, the valve may be caused to open automatically 'in response to any desired refrigerant pressure.

I prefer, however, to eliminate the spring 59 by charging the chamber 54 with several atmospheres of air or other gas which is incondensible at the operating temperatures of the system. As shown in Fig. 7, the gas may be introduced through an opening Ill in the casing 53. Aside from saving a spring and the troubles which attend the use of a spring, an operating advantage is obtained with the compressed air charge, wherein the expansive eifects of higher temperatures on the air charge will raise its pressure slightly, and thus upon commencement of the compressor cycle it will aid the valve to open more rapidly, so that refrigerant may be promptly delivered to the evaporator portions of the system.

I claim:

1. A bellows assembly adapted to constitute a control element for an automatically responsive refrigerant valve comprising a bellows, a casing, said bellows being secured at one end thereof to said casing, a flange on said casing extending inwardly therefrom, said iiange being formed with an aperture of varying diameter 'whereby the aperture, at certain portions thereof, is of greater ldiameter than at other portions, a head member connected to the other end of the bellows, said head member having an end portion adapted to extend through said aperture, said end portion being formed with a reduced neck freely ytting in said aperture when the head, casing, and bellows are assembled in operative relation, the exltremity of said end portion having different diameters, one of which is greater than the minimum.

diameter of said aperture, and. none of which is greater than the maximum diameter of said aperture, whereby said end portion may be passed through said aperture when the greater diameter of the end portion is aligned with the maximum diameter of said aperture, but is held from axial withdrawal upon rotation of the head within saidraperture, said head being so rotated in the assembly, the said reduced neck terminating in a radial flange of greater diameter than said aperture.

2. A bellows assembly adapted to constitute a control element for'an automatically responsive refrigerant valve comprising a bellows, a head secured to one end of said bellows, a casing secured to the other end of said bellows, said head being formed with a. portion .extending laterally toward said casing, said head and portion being bodily movable with said bellows, and with re-l spect to said casingY when the bellows is extended and contracted, said portion and casing being formed with portions of irregular outline, said portions overlapping each other and contacting each other to form a limit stop upon predetermined movement of the bellows with respect to the casing, said portions, in the course of assembly, being relatively rotatable and freely movable past each other when so rotated.

LAWRENCE C. SMITH. 

